Initial Inspection and Diagnostic Overview

Procedure
1. Make sure Headlights and Park Lights operate normally when using the Light Switch before proceeding with Daytime Running Lamp (DRL) diagnosis.
2. Make sure the Brake Warning System is functioning properly. DRL will not turn "ON" if Park Brake is "ON."
3. Check Fusible Link Z for open.
4. Check Turn B-U Fuse 2, Gages Fuse 9 and TAIL LTS Fuse 10 for open. If fuse(s) are blown, replace fuse(s). If fuse(s) re-blows, check for short to ground through the suspected circuit(s).
^ Check for a broken (or partially broken) wire inside of the insulation which could cause system failure but prove "GOOD" in a continuity/voltage check. Use Test Light J 34142 whenever possible. Test lights require more current than a high impedance DVM and are more useful for detecting abnormally high resistive circuits. Some test lights have high impedances and will not be as useful in detecting resistive circuits.
^ Check for proper installation of aftermarket electronic equipment which may affect the integrity of other systems.